Metal-air battery system

Abstract

A metal-air battery system includes: an inlet chamber into which an electrolyte solution flows; an outlet chamber from which the electrolyte solution flows out; a hollow outer electrode having an interior space via which the inlet chamber and the outlet chamber communicate with each other; and an inner electrode disposed to be inserted into the interior space concentrically with the outer electrode. One of the outer electrode and the inner electrode is a negative electrode containing metal, and the other is a porous positive electrode allowing oxygen to diffuse. A flow path through which the electrolyte solution flows from the inlet chamber toward the outlet chamber is formed between the outer electrode and the inner electrode, and the flow path is configured such that a flow-path cross-sectional area thereof decreases from a side of the inlet chamber toward a side of the outlet chamber.

1 . A metal-air battery system, comprising:
 an inlet chamber into which an electrolyte solution flows;   an outlet chamber from which the electrolyte solution flows out;   a hollow outer electrode having an interior space via which the inlet chamber and the outlet chamber communicate with each other; and   an inner electrode disposed to be inserted into the interior space concentrically with the outer electrode,   wherein one of the outer electrode and the inner electrode is a negative electrode containing metal, and the other is a porous positive electrode allowing oxygen to diffuse, and   wherein a flow path through which the electrolyte solution flows from the inlet chamber toward the outlet chamber is formed between the outer electrode and the inner electrode, and the flow path is configured such that a flow-path cross-sectional area thereof decreases from a side of the inlet chamber toward a side of the outlet chamber.   
     
     
         2 . The metal-air battery system according to  claim 1 , wherein the interior space has a truncated conical shape, and the inner electrode has a conical portion or a truncated conical portion corresponding to the truncated conical shape of the outer electrode. 
     
     
         3 . The metal-air battery system according to  claim 2 ,
 wherein the inner electrode has an inlet-side portion upstream of the conical portion or the truncated conical portion in a flow direction of the electrolyte solution, and   wherein the inlet-side portion has a rotationally symmetric shape with respect to an axis of the inner electrode.   
     
     
         4 . The metal-air battery system according to  claim 3 , wherein the inlet-side portion has a hemispherical shape. 
     
     
         5 . The metal-air battery system according to  claim 2 , comprising:
 a moving device for moving the inner electrode along an axis of the inner electrode with respect to the outer electrode.   
     
     
         6 . The metal-air battery system according to  claim 5 ,
 wherein, on a surface of the inner electrode, an insulating layer is disposed in each of an upstream region which is a region upstream in a flow direction of the electrolyte solution and a downstream region which is a region downstream in the flow direction of the electrolyte solution, and   wherein a current-carrying region where the surface is exposed between the upstream region and the downstream region is located in the interior space in both of a case where the inner electrode moves furthest to the side of the outlet chamber and a case where the inner electrode moves furthest to the side of the inlet chamber.   
     
     
         7 . The metal-air battery system according to  claim 5 , comprising:
 a flow control device for controlling a flow rate of the electrolyte solution flowing into the inlet chamber,   wherein the flow control device is configured to control the flow rate of the electrolyte solution according to the movement of the inner electrode.   
     
     
         8 . The metal-air battery system according to  claim 7 ,
 wherein the flow control device includes:
 a first pipe communicating with the inlet chamber; and 
 a second pipe communicating with the first pipe via a hole formed in the first pipe, and 
   wherein the second pipe is configured to move together with the inner electrode and is configured such that an opening area of the hole with respect to the second pipe changes with the movement of the second pipe.   
     
     
         9 . The metal-air battery system according to  claim 5 , comprising:
 a rotating device for rotating either one of the inner electrode or the outer electrode with the axis of the inner electrode or the outer electrode as a rotation center.   
     
     
         10 . The metal-air battery system according to  claim 9 ,
 wherein either the inner electrode or the outer electrode disposed to be rotatable on its axis is a negative electrode, and   wherein the metal-air battery system comprises a load detection device for detecting a load on the rotating device.   
     
     
         11 . The metal-air battery system according to  claim 9 , comprising:
 a voltmeter for detecting a voltage between the outer electrode and the inner electrode;   a differential pressure gauge for detecting a differential pressure between the inlet chamber and the outlet chamber; and   a parameter detection device for detecting a parameter corresponding to an operating time of the metal-air battery system.   
     
     
         12 . The metal-air battery system according to  claim 11 , comprising:
 a control device for controlling the moving device,   wherein the control device determines a movement amount of the inner electrode based on detected values by the voltmeter, the differential pressure gauge, and the parameter detection device, and the moving device moves the inner electrode by the movement amount.   
     
     
         13 . The metal-air battery system according to  claim 12 , wherein the control device is also configured to control the rotating device, and drives the rotating device to rotate the inner electrode or the outer electrode on its axis after the moving device moves the inner electrode. 
     
     
         14 . The metal-air battery system according to  claim 10 , comprising:
 a voltmeter for detecting a voltage between the outer electrode and the inner electrode;   a differential pressure gauge for detecting a differential pressure between the inlet chamber and the outlet chamber;   a parameter detection device for detecting a parameter corresponding to an operating time of the metal-air battery system; and   a control device for controlling the moving device and the rotating device,   wherein the control device determines a movement amount of the inner electrode based on detected values by the load detection device, the voltmeter, the differential pressure gauge, and the parameter detection device, the moving device moves the inner electrode by the movement amount, and the control device drives the rotating device to rotate the inner electrode or the outer electrode on its axis after the moving device moves the inner electrode.   
     
     
         15 . The metal-air battery system according to  claim 1 , wherein the inner electrode is the negative electrode, and the outer electrode is the positive electrode. 
     
     
         16 . The metal-air battery system according to  claim 15 ,
 wherein the outer electrode comprises:
 a charging positive electrode facing the inner electrode; 
 a separator disposed on, of a surface of the charging positive electrode, a face opposite to a face facing the inner electrode; and 
 a discharging positive electrode disposed to be in contact with the separator. 
   
     
     
         17 . The metal-air battery system according to  claim 15 ,
 wherein the inner electrode includes:
 a first hollow portion formed in a part of an interior of the inner electrode; and 
 a second hollow portion formed in a part of the interior of the inner electrode, which is downstream of the first hollow portion in a flow direction of the electrolyte solution, 
   wherein the inner electrode is disposed to penetrate from the inlet chamber and the outlet chamber to respective exteriors thereof, respectively, the first hollow portion communicates with the exterior of the inlet chamber, and the second hollow portion communicates with the exterior of the outlet chamber, and   wherein the inner electrode is formed with through holes via which the first hollow portion and the second hollow portion respectively communicate with a closed space composed of the interior of the inlet chamber, the interior of the outlet chamber, and the flow path.   
     
     
         18 . The metal-air battery system according to  claim 1 ,
 wherein the inner electrode is the positive electrode, and the outer electrode is the negative electrode,   wherein, in the inner electrode, a hollow portion is formed so as to penetrate the inner electrode along the axis of the inner electrode, and   wherein the hollow portion is configured such that an oxygen-containing gas or an oxygen-dissolved electrolyte solution flows.